Project Summary/Abstract: Project 3 Nearly 53 million people live within 3 miles of a Superfund remediation site. Superfund sites contain a wide va- riety of pollutants, including organic chemicals, metals, carbonaceous material, and silica. Although each com- ponent is capable of damage to organisms, their potential to combine into unique hazardous agents has been understudied. Interestingly, when these agents are present together, particularly during thermal treatment (TT), they combine to form particulate matter (PM) with chemisorbed free radicals that persist in the environment and are active in biological systems (environmentally persistent free radicals: EPFRs). EPFRs are produced during TT of hazardous wastes. Nearly 30% of all Superfund sites (non-groundwater) are remediated by TT. EPFR concentrations near Superfund sites range from 1x1018?4x1019 radicals/g of PM. Colfax, LA hosts a haz- ardous waste TT facility, which disposes of fireworks, explosives, and military ordnances. 68% of Colfax?s resi- dents are African American and median household income is $26,149, indicating the community?s institutional vulnerability. Project 3 will measure concentrations of EPFRs to estimate human exposure in Colfax. We will also measure other components of combustion-generated PM across size fractions and detonation-related noise as a co-stressor. Project 3 addresses the three overarching objectives of the 2018 Strategic Plan for the Superfund Research Program. By characterizing EPFRs emitted from this TT site handling hazardous wastes including waste from Superfund sites, we address an issue of high relevance to inform solution-oriented re- search. We will maximize the impact of our program?s investments by coordinating with the Research Transla- tion component of the Administrative Core to facilitate translation of our results to actionable information for the Colfax community. Further, we will coordinate with the Community Engagement Core (CEC) to implement our community-based participatory research model. This novel approach will foster innovation by designing and implementing a field sampling plan for size distributions of EPFRs, size distributions of other PM components, and noise as a co-stressor. The overarching hypothesis of this research is that EPFRs are produced in meas- urable quantities in PM during TT, so that outdoor and in-home EPFR exposure increases with decreasing dis- tance to the source. In Aim 1, we will partner with the Colfax community on plans for assessing exposure to hazardous air pollutants from hazardous waste TT emissions and determine if collaboration will promote com- munity empowerment and engagement on public health advocacy. This work is planned in partnership with two community organizations and in coordination with the CEC. Aim 2 will characterize Colfax residents? exposures to EPFRs in PM by size distribution and composition, how exposures change with distance downwind of the TT facility, and how exposures correlate to detonation-related noise. Aim 3 will characterize in-home concentra- tions of EPFRs and additional chemical and non-chemical stressors among Colfax study participants.